It is well known that a cylindrical electric connector generally includes a housing, an insulation body received in the housing, and a plurality of terminals held in the insulation body. Conventionally, the insulation body for holding and fixing the plurality of terminals is integrally formed. Due to small operation space when connecting a plurality of cables to the plurality of terminals in field, operation of the cylindrical electric connector is inconvenient. Furthermore, the connection portion of such an integral insulation body tends to break up after being folded repeatedly, which reduces its service life.